Spatial profiling system and method
Described herein is a system, a method and a processor-readable medium for spatial profiling. In one arrangement, the described system includes a light source configured to provide outgoing light having at least one time-varying attribute at a selected one of multiple wavelength channels, the at least one time-varying attribute includes either or both of (a) a time-varying intensity profile and (b) a time-varying frequency deviation, a beam director configured to spatially direct the outgoing light into one of multiple directions in two dimensions into an environment having a spatial profile, the one of the multiple directions corresponding to the selected one of the multiple wavelength channels, a light receiver configured to receive at least part of the outgoing light reflected by the environment, and a processing unit configured to determine at least one characteristic associated with the at least one time-varying attribute of the reflected light at the selected one of the multiple wavelengths for estimation of the spatial profile of the environment associated with the corresponding one of the multiple directions.
1. A spatial profiling system including:
a light source configured to provide outgoing light having at least one time-varying attribute at a selected one of multiple wavelength channels, the at least one time-varying attribute including a time-varying intensity profile;
a beam director configured to spatially direct the outgoing light into one of multiple directions in two dimensions into an environment having a spatial profile, the one of the multiple directions corresponding to the selected one of the multiple wavelength channels;
a light receiver configured to receive at least part of the outgoing light reflected by the environment; and
a processing unit configured to determine at least one characteristic associated with the at least one time-varying attribute of the reflected light for estimation of the spatial profile of the environment associated with the corresponding one of the multiple directions,
wherein the light receiver is configured to inhibit detection of non-reflected light based on a difference in wavelength or modulation between the outgoing light and the non-reflected light.
2. The system of claim 1 wherein inhibiting detection of the non-reflected light includes selecting the selected one of the multiple wavelengths based on a predetermined or randomised sequence of wavelength channels.
3. The system of claim 1 wherein inhibiting detection of the non-reflected light includes de-correlating the received light from the outgoing light and incoherently mixing the de-correlated light with a sample of the outgoing light.
4. The system of claim 1 wherein inhibiting detection of the non-reflected light includes performing optical self-heterodyne of the received light with a sample of the outgoing light during a time window within which the light source is configured to provide the sampled light at the selected one of multiple wavelength channels.
5. The system of claim 1 wherein inhibiting detection of the non-reflected light includes imposing a code modulation onto the time-varying intensity profile of the outgoing light according to a coding sequence, and wherein the at least one characteristic includes an autocorrelation of the reflected light with the coding sequence.
6. The system of claim 5 wherein the coding sequence includes a Barker code.
7. The system of claim 5 wherein the coding sequence is adjustable for avoidance of interference with another spatial mapping system.
8. The system of claim 5 wherein the code modulation further includes a slowly-varying Barker code and a fast-varying Barker code.
9. The system of claim 1 wherein the time-varying intensity profile includes periodic modulation at a predetermined frequency.
10. The system of claim 9 wherein the periodic modulation includes sinusoidal modulation, and wherein the at least one characteristics includes a phase shift of the sinusoidally modulated reflected light.
11. The system of claim 9 wherein the periodic modulation includes multiple frequency components, and wherein the at least one characteristic includes at least one of: (a) a delay of an envelope of a beat tone arising from the multiple frequency components to facilitate a coarser and longer-range distance estimation and (b) a phase shift of the periodically reflected light to facilitate a finer and shorter-range distance determination.
12. The system of claim 1 wherein the time-varying intensity profile includes a chirped sinusoidal modulation.
13. The system of claim 1 wherein the light source is configured to provide additional outgoing light having the same or a different time-varying attribute(s) at additionally selected one or more of the multiple wavelength channels in a sequential manner, the beam director is configured to direct the additional outgoing light into the corresponding one or more of the multiple directions in the sequential manner, and the processing unit is configured to determine the at least one characteristic associated with the same or the different time-varying attributes of the reflected light at the additionally selected one or more of the multiple wavelength channels, for estimation of the spatial profile of the environment associated with the corresponding one or more of the multiple directions.
14. The system of claim 13 wherein the sequential manner includes the predetermined sequence.
15. The system of claim 13 wherein the sequential manner includes the randomised sequence.
16. The system of claim 1 wherein the beam director includes reversible optics for (a) spatially directing an outgoing collinear beam from the light source into the multiple directions and (b) spatially directing the reflected light in multiple reversed directions into an incoming collinear beam.
17. The system of claim 16 wherein the reversible optics include a spatially cross-dispersive module.
18. The system of claim 17 wherein the spatially cross-dispersive module includes two spatially dispersive elements in an orthogonal arrangement, each being arranged to steer the outgoing light into respective one of the two dimensions.
19. The system of claim 18 wherein one or both of the two spatially dispersive elements include a photonic crystal structure.
20. The system of claim 1 wherein the system further includes non-reversible optics for routing the outgoing light from the light source to the beam director, and for routing the reflect light from the beam director to the light receiver.
21. The system of claim 20 wherein the non-reversible optics includes an optical circulator.
22. The system of claim 1 wherein the system further includes an optical coupler or beam splitter following the light source.
23. The system of claim 1 wherein the beam director includes collimating optics for routing reflected light collected by bean director to the light receiver along a path not shared by path taken by the outgoing light.
24. The system of claim 1 wherein the beam director is one of multiple beam directors, each of which is (a) optically coupled to the light source and the light receiver, and (b) configured to direct the outgoing light to a respective environment having a respective spatial profile in response to a respective subset of the multiple wavelength channels.
25. The system of claim 24 wherein the beam directors are each fibre-optically coupled to the light source and the light receiver.
26. The system of claim 25 wherein the light receiver is one of multiple light receivers, and the beam directors are each optically coupled to the light source and the respective one of the multiple light receivers.
27. The system of claim 1 wherein the light source includes an etalon module for providing temperature-related information to the processing unit, and the processing unit is configured to control the light source based on the temperature-related information.
28. The system of claim 1 wherein the beam director includes a cavity for obtaining environmental-related information based on intensity of light reflected from the cavity and received by the light receiver.
29. The system of claim 1 wherein the processing unit is further configured to determine at least another characteristic of the reflected light for estimation of a speed of a target in the environment.
30. A spatial profiling method including the steps of:
providing, by a light source, outgoing light having at least one time-varying attribute at a selected one of multiple wavelength channels, the at least one time-varying attribute including a time-varying intensity profile;
spatially directing, by a beam director, the outgoing light into one of multiple directions in two dimensions into an environment having a spatial profile, the one of the multiple directions corresponding to the selected one of the multiple wavelength channels;
receiving, by a light receiver, at least part of the outgoing light reflected by the environment; and
determining, by the processing unit, at least one characteristic associated with the at least one time-varying attribute of the reflected light for estimation of the spatial profile of the environment associated with the corresponding one of the multiple directions,
wherein the light receiver is configured to inhibit detection of non-reflected light based on a difference in wavelength or modulation between the outgoing light and the non-reflected light.
31. A processor-readable medium including instructions, which when executed by a processing unit in a spatial profiling system, cause the system to:
provide, by a light source, outgoing light having at least one time-varying attribute at a selected one of multiple wavelength channels, the outgoing light being spatially directed by a beam director into one of multiple directions in two dimensions into an environment having a spatial profile, the at least one time-varying attribute including a time-varying intensity profile, the one of the multiple directions corresponding to the selected one of the multiple wavelength channels; and
determine, by the processing unit, at least one characteristic associated with the at least one time-varying attribute of at least part of the outgoing light reflected by the environment and received by a light receiver for estimation of the spatial profile of the environment associated with the corresponding one of the multiple directions,
wherein the light receiver is configured to inhibit detection of non-reflected light based on a difference in wavelength or modulation between the outgoing light and the non-reflected light.